Effect of growth hormone on steroidogenesis, insulin-like growth factor-I (IGF-I) and IGF-binding protein-1 production and DNA synthesis in cultured human luteinized granulosa cells.

ABSTRACT

Numerous clinical and experimental observations have suggested that GH is important in ovarian function. We have investigated the effect of GH alone and GH in combination with FSH on the secretion of oestradiol, progesterone, insulin-like growth factor-I (IGF-I) and IGF-binding protein-1 (IGFBP-1) and on [3H]thymidine incorporation in cultured human luteinized granulosa cells. Granulosa cells from patients undergoing treatment for in vitro fertilization were isolated and cultured for 2 days in culture medium with 10% serum. After this preincubation, the medium was removed and the cells were incubated with GH (1, 10 and 100 micrograms/l) with or without FSH in serum-free medium and in the presence of [3H]methylthymidine (2 microCi/ml). GH alone resulted in a significant dose-dependent increase of oestradiol (P < 0.05) and in IGFBP-1 (P < 0.002) in the medium. The release of IGF-I was undetectable and there was no increase in [3H]thymidine incorporation with GH alone. Neither GH nor FSH alone stimulated granulosa cell proliferation or progesterone release, while the combination induced increases (P < 0.001) in both. The stimulatory effect of GH on steroidogenesis, IGFBP-1 production and granulosa cell proliferation supports a putative role for GH in the regulation of ovarian function.